Originally Posted by eshell
I'd suggest not using magnum primers unless proven necessary, and if you're shooting true long range, to check it for ES on your chronograph.
I had used 215Ms in my 6.5-300 Wby with 83 grains of H-870 with decent results, but had to set the 30" barrel back and went with Retumbo in my "new" 27" tube. I continued using the 215M and then found I had wild ES numbers. In theory, this cartridge and powder should definitely require magnum primers, and I always assumed they were mandatory, but I went to a 210 and my ES went way down. I had to add back a grain or two of powder to regain velocity, but it's working well now.
This is very common with cartriges with case capacitys from 50 to 100grs.
The 215 are very hot and won't work in your 25-06 as well as standard rifle
For some reason cases that hold 80 to 90grs of powder seam to be the most
sensitive to primer changes.
With out exception all of my testing with this size cartrige shot 30 to 50ft/sec
faster with the Fed 215s but SD's and ES's sufferd (30 to 50 ft/sec spread)
but when I switched to Rem 9 1/2 M's (A cooler mag primer) velocity slowed
and SD's dropped to below 15 ft/sec.
The 25-06 will hold around 60grs so you will get better results with an even cooler
primer like the fed 210M,rem9-1/2 LR or the CCI BR2. I have had good luck with
all three of these primers in 06 size cases and velocity has been within 5 ft/sec
of each other.
My records show that the CCI BR2 worked best in the 25-06 But all rifles are different
and this could be true for your rifle.
I hope this helped
J E CUSTOM